大豆皂苷Bb预处理对脑缺血再灌模型大鼠的神经保护作用

Neuroprotective effect of soyasaponin Bb pretreatment in cerebral ischemia/reperfusion model rats

目的 探讨大豆皂苷Bb(soyasaponin Bb, SSBb)预处理对脑缺血/再灌注(ischemia/reperfusion, I/R)大鼠的神经保护作用。方法 将SD大鼠分为假手术组、模型组和低、高剂量SSBb预处理组,每组15只大鼠。通过线栓法建立大脑中动脉闭塞(middle cerebral artery occlusion, MCAO)大鼠模型,并于闭塞后2 h实现再灌注,用来模拟脑I/R。低、高剂量SSBb预处理组在MCAO术前1 h分别灌胃20和50 mg/kg SSBb。再灌注24 h后,用改良神经损伤严重缺损评分表(modified neurological severity score, mNSS)评估神经功能缺陷,用2,3,5-三苯基氯化四氮唑(2,3,5-triphenytetrazolium chloride, TTC)检测脑梗死体积,用微管相关蛋白-2(microtubule-associated protein-2,MAP-2)染色法评估神经元损伤,用干/湿称重法检测脑含水量,用免疫荧光法检测缺血半暗带中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)表达水平,用Western blot检测突触后致密蛋白-95(postsynaptic density-95,PSD-95)、突触素I(synapsin I)和突触结合蛋白(synaptotagmin)的表达水平。结果 与模型组比较,低和高剂量SSBb预处理均能显著改善MCAO模型大鼠的神经功能缺陷、减轻脑水肿和脑梗死,并降低缺血半暗带中TNF-α的表达水平和PSD-95、synapsin I和synaptotagmin的表达水平(均P<0.01和P<0.001);其中高剂量组作用最为显著(P<0.001)。结论 SSBb预处理在脑I/R损伤大鼠中发挥的神经保护作用。

Objective To investigate the neuroprotective effect of soyasaponin Bb(SSBb) pretreatment in cerebral ischemia/reperfusion(I/R) rats. Methods SD rats were divided into sham, model, and low-and high-dose SSBb pretreatment groups with 15 rats each. A rat model of middle cerebral artery occlusion(MCAO) was established by suture occlusion, and reperfusion was performed 2 h after occlusion to simulate brain I/R. Low-and high-dose SSBb pretreatment groups were administered 20 and 50 mg/kg SSBb by gavage, respectively, at 1 h before MCAO. At 24 h after reperfusion, neurological deficits were assessed by the modified neurological severity score, and cerebral infarct volume was measured by 2,3,5-triphenyltetrazolium chloride staining. Microtubule-associated protein-2 staining was used to assess neuronal damage. Brain water content was measured by the dry/wet weight. Tumor necrosis factor-α(TNF-α) expression in ischemic penumbra was measured by immunofluorescence. Postsynaptic density-95(PSD-95), synapsin I and synaptotagmin expression was detected by Western blot. Results Compared with the model group, low-and high-dose SSBb pretreatment significantly improved neurological dysfunction, alleviated cerebral edema and cerebral infarction in MCAO model rats, and decreased expression of TNF-α, PSD-95, synapsin I and synaptotagmin in ischemic penumbra(P<0.01 or P<0.001). The effects in the high-dose group were most significant(P<0.001). Conclusions SSBb pretreatment has a neuroprotective effect in rats with cerebral I/R injury.